#include<stdio.h>
#include<math.h>
int main()
{
	double h,s,v,l,k,n;
	double t1,t2;
	int s1,s2;
	scanf("%lf %lf %lf %lf %lf %lf",&h,&s,&v,&l,&k,&n);
	t1=sqrt((h-k)/5.0);
	t2=sqrt(h/5.0);
	s1=(s-v*t1+l);
	s2=(s-v*t2);
	if(s1>=n)
	{
		s1=n;
	}
	if(s2<=0)
	{
		s2=0;
	}
	printf("%d",s1-s2);
	return 0;
}
